In downhole drilling and completion industries, it is frequently necessary to seal the annular space between a borehole wall and a tubular therewithin. Such sealing can be accomplished by a number of different sealing mechanisms including swellable seals.
One example of swellable seals in the art is known commercially as a Reactive Element Packer or REPacker™ reactive element packer, available from Baker Oil Tools, Houston Tex. REPackers are commercial isolation tools that use elastomer swelling technology to provide a barrier in surrounding member/open hole and surrounding member/surrounding member annuli. Such packers may have a water reactive section, an oil reactive section, or both. A water reactive section may include water-absorbing particles incorporated in nitrile-based polymer. These particles swell via absorbing water, which in turn expands the rubber without being physically absorbed into the rubber matrix, which can adversely affect properties. Similarly, an oil reactive section may include hydrocarbon-absorbing rubbers and polymers, in which uptake of the hydrocarbon by the polymer causes swelling and lubricates and decreases the mechanical strength of the polymer chain as it expands.
However, under certain circumstances, it may be impractical to deploy a seal or packer having one or the other of a water or oil swellable section based on availability of swelling material, or other considerations including environmental considerations. The art would well receive seals responsive to a wider variety of swelling materials, while maintaining or increasing the swelling ability and effectiveness of the swelled material.